Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/0427—Coating with only one layer of a composition containing a polymer binder
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2463/00—Characterised by the use of epoxy resins; Derivatives of epoxy resins
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S166/00—Wells
  • Y10S166/902—Wells for inhibiting corrosion or coating

Definitions

• This invention relates to a process for protecting, repairing and thereby extending the life of plastic and plastic composite materials.
• Plastic and plastic composite materials are receiving widespread application as stress-bearing structural members because of weight, strength and cost advantages over metal counterparts which perform substantially the same function. These materials can also be used as coatings and liners thereby preventing the direct environmental exposure of an internal substrate which may be the major stress-bearing element (ex. coatings on metal pipe and tubing).
• plastic and plastic composite materials are also susceptible to degradation from environmental exposure to various gases, liquids, solids, radiation and heat. The resulting degradation can occur rapidly or over a long term (aging) and can result in an overall reduction in the mechanical strength of a given component.
• the various degradation processes can interact and thereby increase the susceptibility of the plastic or plastic composite material to the degrade.
• the sorption of moisture by epoxies is often accompanied by a lowering of the glass transition temperature. This sorption then causes the epoxies to soften at lower temperatures and to also undergo a deterioration in mechanical response.
• the aging characteristics of epoxy composite matrixes in many service environments depend on the degree of deterioration of the high temperature mechanical properties caused by the sorption and accompanying plasticizing effect of sorbed moisture.
• Sorbed moisture in epoxies can also cause epoxy matrixes to swell and the resulting stresses from swelling can significantly affect the durability of composite matrixes.
• Swelling stresses caused by moisture gradients, together with other stresses inherent in the material, such as fabrication stresses, can be of such magnitude as to cause localized fracturing of the polymer matrix.
• This localized fracturing can then increase the matrix permeability to other gases and when used as a lining or coating, reduce the effectiveness of the matrix medium to protect specific items such as metals from exposure to corrosive environments.
• the moisture induced swelling of epoxies generally results in only a one to two percent increase in thickness, dimensional changes of this magnitude in a composite material are sufficient to produce significant internal stresses as the fibers attempt to constrain the swelling. Absorbed moisture has also been shown to reduce the tensile strength and moduli of fresh epoxies and to enhance cavitation.
• the plastic composition and the strength of plastics can also be detrimentally affected by environmental exposure through oxidation and hydrolysis at elevated temperatures.
• oxidation of epoxies occurs at 150° to 200° C. and hydrolysis at 225° to 300° C.
• the solid components about which the plastic medium is placed can also be degraded by environmental effects.
• carbon and aromatic polyamide fiber can lose strength by oxidation.
• the hydrolysis of aromatic polyamide fiber is strongly catalyzed by acids and bases.
• Degradation by the erosion of plastic surfaces can also result in a corresponding reduction in strength for plastics and plastic composites as the amount of stress-bearing material is reduced and highly active sites are provided for the various degradation processes.
• Yet a further object of this invention is to provide a process for repairing degraded plastic and plastic composite materials.
• a still yet further object of this invention is to provide a process for protecting and/or repairing items constructed of, lined or coated with plastic or plastic composite material in an in-situ manner at elevated temperatures and pressures.
• a process for treating plastic and plastic composite materials wherein a protective epoxy coating is placed on said material by contacting with a composition comprising an epoxy resin, an effective amount of curing agent for the epoxy resin, an alcohol and a hydrocarbon solvent.
• the protective epoxy coating is applied by a process comprising the sequential contacting of the plastic or plastic composite material with a first hydrocarbon solution comprised of an epoxy resin and a hydrocarbon solvent, and a second hydrocarbon solution comprised of an alcohol, a curing agent, and a hydrocarbon solvent.
• the plastic or plastic composite material to be treated may be comprised entirely of plastic or plastic composite, may be one of many components in a system of which not all parts are plastic or plastic composite, or may be a portion of a given object such as a coating or liner.
• items which may be treated include tubing, piping, and related flow equipment such as valves, connectors, and pumps which are constructed of, lined or coated with a plastic or plastic composite.
• the protective epoxy coating i.e., film
• Coatings or films are generally distinguished from linings in terms of thickness. Linings are generally greater than 0.5 mm whereas coatings or films are less than 0.5 mm.
• Plastics are polymeric materials which are commonly divided into two classes, thermoplastic and thermosetting. Both classifications possess useful corrosion resistant properties.
• Thermoplastics are materials which under suitable temperature conditions are permanently plastic, that is they can be softened by heat over and over again without any hardening taking place. Examples include, but are not limited to, polyethylene, polypropylene, polyvinylacetate, poly(vinyl chloride), polyamide, polystyrene, polycarbonate, polysulfone, polyphenylsulfide, and certain polyesters, polyurethanes and polyimides.
• thermosetting resins are converted by heat or by heat and pressure into permanently infusible materials.
• a preferred plastic and a preferred medium for the plastic composite are the thermoset plastics and the higher melting point thermoplastics.
• Thermoset plastics are more preferred and thermoset plastics selected from the group consisting of phenolic, epoxy, urethane, polyimide and mixtures thereof are still more preferred.
• the more preferred thermoset plastic and plastic medium for the practice of the herein claimed invention are selected from the group consisting of phenolic, epoxy and mixtures thereof.
• the most preferred plastic and plastic mediums are those comprised of epoxy.
• the most preferred thermoplastic for the practice of this invention is polyamide and the most preferred polyamide is nylon.
• the mixture can be introduced as slugs and immiscible or miscible fluids used as displacing agents. Fluid mixing can be minimized by displacing the slugs in a gravity stable manner. Similarly, fluid slugs can be used in horizontal systems but slug volume must be sufficient to account for slug dilution at the front and back ends of the slugs from mixing with the upstream and downstream fluids.
• the single treatment mixture or the two treatment mixtures applied sequentially can be separated from the upstream and downstream fluids and each other by the use of mechanical pigs.
• the solution must remain in contact with the surface for a time sufficient or effective to form a protective coating thereon.
• the treatment composition can be applied as one solution, or alternatively it can be applied by contacting the surfaces sequentially with a solution of the curing agent and a solution of the epoxy resin.
• the resin solution and amine solution can be pumped from separate storage tanks to a static mixer at a T-juncture immediately prior to pumping the mixture downhole.
• the following down-well treatment methods can be used to apply the composition to the plastic and plastic composite surfaces of equipment used to recover natural fluids from a subterranean reservoir.
• the treatment fluid comprising alcohol, epoxy resin, curing agent and hydrocarbon diluent is introduced preferably in an oil carrier into the annulus of a cased wellbore between the casing and the tubing.
• the well is returned to production and the injected compositions are gradually returned with the produced fluids, effecting en route the coating of contacted plastic surfaces with a protective film.
• a liquid column of the treating agent can be placed in the tubing or the annular space and allowed to stand for a time which can range from 10 minutes to 24 hours before resuming production, usually at least 2 hours.
• the treatment fluid is injected into the annular space of a cased wellbore, the well is closed off, and the composition is continuously circulated with well fluids down the annulus and up the tubing for an extended period of time which can vary widely but will usually be between 6 and 48 hours. At the end of the determined time period, the well is returned to production.
• a highly concentrated slug of the treatment fluid for example about 27 weight percent alcohol, about 27 weight percent amine, about 15 weight percent epoxy resin, about 31 weight percent hydrocarbon diluent, is injected into the tubing of a cased borehole and pressured down the tubing with a fluid column of a brine solution such as 2 weight percent aqueous potassium chloride. When the pressure is released, the aqueous brine column and the treatment fluid are produced up the tubing.
• the composition as a concentrated slug thus contacts the plastic and plastic composite walls of the tubing and lays down a protective film as it flows in a downward and upward circuit.
• the nature of the film thus formed can vary according to the particular composition used and the environment in which it is applied, but it has been found that the film will generally be a soft, sticky layer adhering to the plastic surface. It is not necessary that the composition harden to a tough coating, and it has been found in laboratory runs that the applied film tends to maintain a tacky or greasy consistency.
• any epoxy resin having, on the average, more than one vicinal epoxide group per molecule can be used in the inventive process.
• the epoxy resin may be saturated or unsaturated, aliphatic, cycloaliphatic, aromatic or heterocyclic, and may bear substituents which do not materially interfere with the curing reaction. These substituents may be monomeric or polymeric.
• Suitable epoxy resins include glycidyl ethers prepared by the reaction of epichlorohydrin with a polyhydric alcohol under alkaline reaction conditions. The overall reaction and the resulting epoxy resin products obtained when epichlorohydrine is reacted with the polyhydric alcohol bisphenol A is set out below.
• the product is represented by structure (I) wherein n is zero or a number greater than 0, commonly in the range of 0 to 10, preferably in the range of 0 to 2. ##
• epoxy resins can be prepared by the reaction of epichlorohydrin with mononuclear di- and tri-hydroxy phenolic compounds such as resorcinol and phloroglucinol, selected polynuclear polyhydroxy phenolic compounds such as bis(p-hydroxyphenyl)methane and 4,4'-dihydroxy biphenyl, or aliphatic polyols such as 1,4-butanediol and glycerol.
• mononuclear di- and tri-hydroxy phenolic compounds such as resorcinol and phloroglucinol
• selected polynuclear polyhydroxy phenolic compounds such as bis(p-hydroxyphenyl)methane and 4,4'-dihydroxy biphenyl
• aliphatic polyols such as 1,4-butanediol and glycerol.
• Epoxy resins suitable for use in the invention have molecular weights generally within the range of 50 to about 10,000, preferably about 200 to about 1500.
• Presently preferred for the invention is the commercially available Epon 828 epoxy resin, a reaction product of epichlorohydrin and 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) and having a molecular weight of about 400, an epoxide equivalent (ASTM D-1652) of about 185-192, and an n value in structure (I) above of about 0.2.
• suitable polyepoxides can be derived from esters described by formula (IV) prepared from unsaturated alcohols and unsaturated carboxylic acids: ##STR4## wherein R" represents alkenyl and cycloalkenyl groups containing 4 to 12 carbon atoms and R"' represents alkenyl and cycloalkenyl groups containing 4 to 12 carbon atoms.
• polyepoxides derived from the latter include the following: dimethyl 3,4,7,8-diepoxydecanedioate; dibutyl 3,4,5,6-diepoxycyclohexane-1,2-carboxylate; dioctyl 3,4,7,8-diepoxyhexadecanedioate; diethyl 5,6,9,10-diepoxytetradecanedioate and the like.
• Dimers of dienes such as 4-vinyl cyclohexene-1 from butadiene and dicyclopentadiene from cyclopentadiene can be converted to epoxidized derivatives which are suitable for use in the instant process.
• Curing agents suitable for use in the invention composition and process include compounds having amino hydrogen atoms. These include aliphatic, cycloaliphatic, aromatic and heterocyclic amines.
• curing compounds include aliphatic polyamines such as ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, 1,4-aminobutane, 1,3-diaminobutane, hexamethylenediamine, 3-(n-isopropylamino)propylamine, N,N'-diethyl-1,3-propanediamine, hexapropyleneheptamine, penta(1-methyl-propylene)hexamine, tetrabutylenepentamine, hexa-(1,1-dimethylethylene)-heptamine, di(1-methylbutylene)triamine, pentaamylenehexamine, tri(1,2,2-trimethylethylene)tetramine, tetra(1,3-d
• a class of polyamines particularly suitable for use in the invention are N-alkyl- and N-alkylenyl-substituted 1,3-diaminopropanes and mixtures thereof.
• Examples of such polyamines include N-hexadecyl-1,3-diaminopropane, N-tetradecyl-1,3-diaminopropane, N-octadecyl-1,3-diaminopropane, N-pentadecyl-1,3-diaminopropane, N-heptadecyl-1,3-diaminopropane, N-nonadecyl-1,3-diaminopropane, and N-octadecenyl-1,3-diaminopropane.
• N-alkylated and N-alkenylated diamines can be used in the invention.
• the presently preferred polyamine is a commercial product sold under the trademark Duomeen T. This product is N-tallow-1,3-diaminopropane in which the majority of the tallow substituent groups are alkyl and alkenyl containing from 16 to 18 carbon atoms each, with a minority of substituent groups having 14 carbon atoms each.
• compositions using Duomeen T stems are thought to result from its relatively high molecular weight, which produces a long-chain "net” to cover the plastic or plastic composite surface, its polyfunctionality, and its relatively high boiling point, which permits its use in high-temperature environments.
• Other commercially available materials include N-coco-1,3-diaminopropane which the majority of the coco substituent groups contain 12 to 14 carbon atoms, commerically available under the tradename Duomeen C, and N-soya-1,3-diaminopropane, which contains C 18 alkenyl groups along with a minor proportion of C 16 alkyl groups.
• coco and tallow amines are also very effective in producing corrosion inhibiting compositions.
• Cocoamine as discussed above contain coco substituent groups which are alkyl and/or alkenyl groups, containing from 12 to 14 carbon atoms each and is commercially available under the tradename Armeen C (C 12 H 25 NH 2 ).
• Tallowamines also discussed above contain tallow substituent groups which are alkyl and/or alkenyl, containing from 16 to 18 carbon atoms each, with a minority of substituent groups containing 14 carbon atoms each.
• Other monoamines which may be used as curing agents include octylamine, dodecylamine, hexadecylamine, oleyamine, soyaamine, dicocoamine and dihydrogenated tallowamine.
• Additional polyamines suitable for use in the invention can contain 3 or more nitrogen atoms as illustrated by the following examples: N-dodecyl-diethylenetriamine, N-tetradecyl-diethylene triamine, N-tetradecyl-dipropylenetriamine, N-tetradecyl triethylene tetramine and the corresponding N-alkenyl triamines.
• curing agents which can be used include polyfunctional nitrogen-containing compounds such as, for example, amino acids, amino alcohols, amino nitriles, and amino ketones; sulfonic acids; carboxylic acids; and organic anhydrides.
• Alcohols suitable for use in the invention include any alkanols containing at least one --OH functional group. These include alcohols containing 1 to about 15 carbon atoms such as methanol, ethanol, 1-propanol, 2-propanol, butanols, pentanols, hexanols, heptanols, octanols, 1-pentadecanol, and mixtures of these.
• the most suitable alcohols include alcohols selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, n-butanol, n-pentanol, n-hexanol, n-heptanol and combinations of any two or more thereof.
• Polyols containing 1 to 5 carbon atoms such as ethylene glycol, 1,3-propanediol, 2,3-butanediol, glycerol and pentaerythritol can also be used.
• methanol is preferred, particularly in a treatment composition containing xylene as the aromatic hydrocarbon diluent, Epon 828 as the epoxy resin, and Duomeen T as the polyamine, because Duomeen T is soluble in methanol at room temperature and because of the effectiveness of the resulting treatment process.
• a hydrocarbon diluent is used for the invention composition.
• hydrocarbon diluents suitable for use in the treating agents include the isomeric xylenes, toluene, benzene, naphtha, cyclohexylbenzene, fuel oil, diesel oil, heavy aromatic oils, Stoddart solvent, crude oil, and condensate from gas wells.
• xylene is the preferred hydrocarbon diluent because it is an effective solvent for the other preferred components and because of the corrosion-inhibiting effectiveness of the resulting composition.
• the higher-boiling aromatic hydrocarbons are particularly useful as diluents when operating in deeper wells with higher downhole temperatures and in high-temperature gas and oil wells generally.
• temperature and pressure are not key parameters and operation at temperatures of 300° F. and higher and/or pressures of 6000 psia and higher is possible.
• a carrier liquid or drive fluid to force a slug of the corrosion-inhibiting composition into the well vessel or pipe being treated.
• Any of the hydrocarbons listed above as suitable diluents may be used.
• diesel oil, sea water or condensate from the well being treated are preferred carrier fluids.
• Various alcohol-aromatic hydrocarbon azeotropes can be used in the invention compositions to supply at least partially the diluent and the alcohol components.
• Representative azeotropes include the following, with the weight percent of each component in parenthesis: methanol (39)/benzene (61); ethanol (32)/benzene (68); 2-propanol (33)/benzene (67); 1-propanol (17)/benzene (83); isobutyl alcohol (9)/benzene (91); 1-butanol (68)/p-xylene (32); 2-pentanol (28)/toluene (72) and hexanol (13)/p-xylene (87). It is also contemplated that impure alcohol streams such as mixed butanols resulting from Oxo technology using propylene feedstock can be used in the treating compositions.
• the components of the inventive process can be mixed in any order, but it is presently preferred to dissolve the epoxy resin in a hydrocarbon and add an amine/alcohol/hydrocarbon mixture to this solution.
• a batch of the treating composition can be prepared by mixing a first solution of alcohol, hydrocarbon and amine in, for example, approximately a 1:1:1 (mL:mL:g) ratio and a second solution of an epoxy resin in a hydrocarbon in about a 3:1 (g:mL) ratio.
• the treatment fluid is then prepared by mixing the first and second solutions in such proportions that the weight ratio of polyamine to epoxy resin in the final solution varies over the broad range of about 1000:1 to 1:500, preferably about 100:1 to 1:50, and most preferably about 10:1 to 1:5.
• the weight percent of alcohol in the final composition varies over the broad range of 1 to 99%, preferably 10 to 60%, and most preferably 20 to 30%.
• the hydrocarbon diluent can be present in any concentration range in which the invention composition remains in an essentially fluid pumpable state.
• a particularly suitable composition contains an equivalent ratio of polyamine to epoxy of greater than about 1:1, preferably about 1.25:1 to 10:1, most preferably about 1.5:1 to 5:1.
• the protective film obtained with such an amine-rich system generally has, in contrast to the hard coatings obtained with conventional cured epoxy systems, a tacky, comparatively soft consistency.
• the polyamine:epoxy molar ratio corresponding to the preferred equivalent ratios above depends, of course, on the relative number of functional groups of the specific compounds used, and these ratios can be computed by methods known in the art. For example, for a polyamine containing 3 active hydrogen atoms and an epoxy resin having an average of 2 epoxide groups per molecule, the stoichiometric molar ratio of polyamine:epoxy resin is 0.67:1.
• the preferred compositions containing such polyamines and epoxy resins have a molar ratio of at least about 0.8:1, preferably within the range of about 1.1:1 to 10:1, most preferably about 1.25:1 to 6:1.
• the corresponding volume amounts for the preferred components are generally at least about 1.0:1, preferably about 1.3:1 to 12:1, most preferably about 1.5:1 to 7:1.
• the solution consisted of 950 mL of synthetic brine (87.05 g CaCl 2 .2H 2 O, 39.16 g MgCl 2 .6H 2 O and 2,025. g NaCl per 5 gal. distilled H 2 O) and 50 ml kerosene.
• the inhibitor was prepared by combining 1 part epoxy resin/hydrocarbon solution (A) with 2 to 4 parts amine/alcohol/hydrocarbon solution (B) wherein the epoxy resin was Epon 828®; the hydrocarbon solution was xylene; the amine was Duomeen T®; and the alcohol was methanol.
• the ratio of A:B for the first treatment in Table I was 1:2 whereas the ratio for those probes receiving a second treatment was 1:4.
• the coated electrodes which had been damaged by environmental exposure were treated by dipping the electrode into the inhibitor for 1 second and then drying at room temperature for about 1 hr.
• Table I The test results are tabulated in Table I and show that the corrosion inhibitor repaired and thereby prolonged the useful life of all coatings.
• the first column in Table I shows the commercially available coatings which were placed on the carbon-steel electrode.
• the second column shows the general component make-up.
• the thickness of the coating is shown in column 3.
• Column 4 shows the corrosion rate of all coatings after 60 hrs. exposure to the environmental conditions previously discussed. All probes were then treated with inhibitor. After the treatments, the corrosion rates decreased to zero and remained at zero for 72 hours (column 5). Seventy-two hours following inhibitor treatment, the fluid in the flasks were changed and the corrosion rates for probes coated with TK-2, TK-7 and TK-99 were observed to increase. Corrosion rates 24 hrs.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Paints Or Removers (AREA)
• Treatments Of Macromolecular Shaped Articles (AREA)
• Epoxy Resins (AREA)

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• 1992
  • 1992-12-10 US US07/988,662 patent/US5318805A/en not_active Expired - Lifetime
• 1993
  • 1993-09-28 CA CA002107178A patent/CA2107178C/en not_active Expired - Fee Related
  • 1993-11-25 NZ NZ250281A patent/NZ250281A/xx unknown
  • 1993-12-03 MX MX9307648A patent/MX9307648A/es not_active IP Right Cessation
  • 1993-12-07 MY MYPI93002616A patent/MY109733A/en unknown
  • 1993-12-09 DE DE69330551T patent/DE69330551T2/de not_active Expired - Fee Related
  • 1993-12-09 EP EP93119854A patent/EP0613932B1/en not_active Expired - Lifetime
  • 1993-12-10 JP JP31064193A patent/JP3223223B2/ja not_active Expired - Fee Related
  • 1993-12-10 NO NO19934552A patent/NO310978B1/no not_active IP Right Cessation

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